Thromboembolic events and hemorrhagic stroke after mRNA (BNT162b2) and inactivated (CoronaVac) covid-19 vaccination: A self-controlled case series study.

Background: This study aims to evaluate the association between thromboembolic events and hemorrhagic stroke following BNT162b2 and CoronaVac vaccination. Methods: Patients with incident thromboembolic events or hemorrhagic stroke within 28 days of covid-19 vaccination or SARS-CoV-2 positive test during 23 February to 30 September 2021 were included. The incidence per 100,000 covid-19 vaccine doses administered and SARS-CoV-2 test positive cases were estimated. A modified self-controlled case series (SCCS) analysis using the data from the Hong Kong territory-wide electronic health and vaccination records. Seasonal effect was adjusted by month. Findings: A total of 5,526,547 doses of BNT162b2 and 3,146,741 doses of CoronaVac were administered. A total of 334 and 402 thromboembolic events, and 57 and 49 hemorrhagic stroke cases occurred within 28 days after BNT162b2 and CoronaVac vaccination, respectively. The crude incidence of thromboembolic events and hemorrhagic stroke per 100,000 doses administered for both covid-19 vaccines were smaller than that per 100,000 SARS-CoV-2 test positive cases. The modified SCCS detected an increased risk of hemorrhagic stroke in BNT162b2 14-27 days after first dose with adjusted IRR of 2.53 (95% CI 1.48-4.34), and 0-13 days after second dose with adjusted IRR 2.69 (95% CI 1.54-4.69). No statistically significant risk was observed for thromboembolic events for both vaccines. Interpretation: We detected a possible safety signal for hemorrhagic stroke following BNT162b2 vaccination. The incidence of thromboembolic event or hemorrhagic stroke following vaccination is lower than that among SARS-CoV-2 test positive cases; therefore, vaccination against covid-19 remains an important public health intervention. Funding: This study was funded by a research grant from the Food and Health Bureau, The Government of the Hong Kong Special Administrative Region (reference COVID19F01).

Self-reported reactogenicity of CoronaVac (Sinovac) compared with Comirnaty (Pfizer-BioNTech): A prospective cohort study with intensive monitoring.

OBJECTIVE: CoronaVac (Sinovac) Covid-19 vaccine has recently been approved for emergency use by the World Health Organization. However, data on its reactogenicity in real-world settings is scant. This study aimed to compare self-reported post-vaccination adverse reactions between CoronaVac and Comirnaty (Pfizer-BioNTech). METHODS: We adopted a prospective cohort study design using online surveys from the day of first-dose vaccination with intensive follow-up through two weeks after the second dose (11 time points). The primary outcome was adverse reactions (any versus none) and secondary outcomes were the sub-categories of adverse reactions (local, systemic, and severe allergic reactions). Potential effect modification across multimorbidity status, older age, and sex was examined. RESULTS: In total, 2,098 participants who were scheduled to complete the 14th-day survey were included, with 46.2% receiving Comirnaty. Retention rate two weeks after the second dose was 81.0% for the CoronaVac group and 83.6% for the Comirnaty group. Throughout the follow-up period, 801 (82.7%) of those receiving Comirnaty and 543 (48.1%) of those receiving CoronaVac reported adverse reactions. Adjusted analysis suggested that compared with Comirnaty, CoronaVac was associated with 83%-reduced odds of any adverse reactions [adjusted odds ratio (AOR) = 0.17, 95% confidence interval (CI) 0.15-0.20], 92%-reduced odds of local adverse reactions (AOR = 0.08, 95% CI 0.06-0.09), and 76%-reduced odds of systemic adverse reactions (AOR = 0.24, 95% CI 0.16-0.28). No significant effect modification was identified. CONCLUSION: This post-marketing study comparing the reactogenicity of Covid-19 vaccines suggests a lower risk of self-reported adverse reactions following vaccination with CoronaVac compared with Comirnaty.

Scarlet fever epidemic, Hong Kong, 2011.

More than 900 cases of scarlet fever were recorded in Hong Kong during January-July, 2011. Six cases were complicated by toxic shock syndrome, of which 2 were fatal. Pulsed-field gel electrophoresis patterns suggested a multiclonal epidemic; emm12 was the predominant circulating type. We recommend genetic testing of and antimicrobial resistance monitoring for this reportable disease.

Prevention of acute myocardial infarction and stroke among elderly persons by dual pneumococcal and influenza vaccination: a prospective cohort study.

BACKGROUND: Despite World Health Organization recommendations, the rate of 23-valent pneumococcal (PPV) and influenza (TIV) vaccination among elderly persons in Hong Kong, China, is exceptionally low because of doubts about effectiveness of vaccination. The efficacy of dual vaccination remains unknown. METHODS: From 3 December 2007 to 30 June 2008, we conducted a prospective cohort study by recruiting outpatients aged ≥65 years with chronic illness to participate in a PPV and TIV vaccination program. All were observed until 31 March 2009. The outcome of subjects, including the rates of death, hospitalization, pneumonia, ischemic stroke, acute myocardial infarction, and coronary and intensive care admissions, were determined. RESULTS: Of the 36,636 subjects recruited, 7292 received both PPV and TIV, 2076 received TIV vaccine alone, 1875 received PPV alone, and 25,393 were unvaccinated, with a duration of follow-up of 45,834 person-years. Baseline characteristics were well matched between the groups, except that there were fewer male patients in the PPV and TIV group and fewer cases of comorbid chronic obstructive pulmonary disease among unvaccinated persons. At week 64 from commencement of the study, dual-vaccinees experienced fewer deaths (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.55-0.77]; P<.001) and fewer cases of pneumonia (HR, 0.57; 95% CI, 0.51-0.64; P<.001), ischemic stroke (HR, 0.67; 95% CI, 0.54-0.83; P<.001), and acute myocardial infarction (HR, 0.52; 95% CI, 0.38-0.71; P<.001), compared with unvaccinated subjects. Dual vaccination resulted in fewer coronary (HR, 0.59; 95% CI, 0.44-0.79; P<.001) and intensive care admissions (HR, 0.45; 95% CI, 0.22-0.94; P=.03), compared with among unvaccinated subjects. CONCLUSIONS: Dual vaccination with PPV and TIV is effective in protecting elderly persons with chronic illness from developing complications from respiratory, cardiovascular, and cerebrovascular diseases, thereby reducing hospitalization, coronary or intensive care admissions, and death.

Epidemiological analysis of Streptococcus pyogenes infections in Hong Kong.

AIMS: The aim of this study was to characterise clinical and microbiological features of isolates obtained from both invasive and non-invasive Streptococcus pyogenes infections in Hong Kong, between October 2005 and April 2008. METHOD: Clinical data of invasive isolates were collected retrospectively. Altogether 281 isolates were emm sequence typed and tested for antimicrobial susceptibility using disk diffusion method. Detection of the presence of the streptococcal pyrogenic exotoxin genes was also carried out. RESULTS: emm1, emm4 and emm12 were the most prevalent in both the invasive and non-invasive groups with an increase in incidence of emm22 compared with a previous study. emm22 was associated with invasive cellulitis and wound infection. The overall rate of erythromycin resistance was 25.6% and was significantly higher in emm22 strains (85.7%). The phage-encoded superantigen gene speA was exclusively associated with emm1 in both invasive and non-invasive isolates. CONCLUSION: This study revealed a changing epidemiology of S. pyogenes infection in Hong Kong, with a unique pattern compared with other Asian countries. Invasiveness is not related to the presence of speA, speC or ssa genes and the antimicrobial resistance rate was high for macrolides. The findings have an implication on the use and efficacy of the polyvalent S. pyogenes vaccine under development.

Quinolone resistance and correlation to other antimicrobial resistances in faecal isolates of Escherichia coli in Hong Kong.

In an attempt to assess the level of quinolone resistance and its association with other antimicrobial resistance in faecal Escherichia coli isolated from routine outpatient specimens in Hong Kong, ciprofloxacin-supplemented MacConkey agar was used to screen for resistant isolates. Antimicrobial susceptibility testing of the isolates was done by VITEK 2 and previous amplification-based methods were employed to characterize the genetic determinants behind some of the resistance phenotypes. One hundred and seventy-six (43%) of 409 specimens had quinolone-resistant E. coli isolated (199 isolates). Quinolone resistance was found to be associated with resistances to penicillins (>80%) and co-trimoxazole (69%). Nonsusceptibility to combinations of penicillins and clavulanic acid was above 20% and up to 50% for the aminoglycosides gentamicin and tobramycin. CTX-M-type extended-spectrum beta-lactamases were found responsible for most cephalosporin resistances but the transferable quinolone resistance determinant qnrA was not detected. Our data suggested that a high percentage of E. coli isolates as part of the alleged normal intestinal microflora in humans appeared to be resistant to quinolones. Co-resistance to various other frequently used antimicrobials was also observed. Transferable genetic determinants were found to be involved in some cases.

Rapid pulsed-field gel electrophoresis protocol for subtyping of Streptococcus suis serotype 2.

A rapid pulsed-field gel electrophoresis (PFGE) protocol for subtyping of Streptococcus suis serotype 2 was developed and evaluated using 27 clinical isolates from 22 epidemiologically unrelated patients. Results were matched against antibiogram, virulence genotyping and multi locus sequence typing (MLST). PFGE appeared to be the most discriminatory with numerical index of discrimination (D) equal to 0.87.

Plasmid-mediated resistance to ciprofloxacin and cefotaxime in clinical isolates of Salmonella enterica serotype Enteritidis in Hong Kong.

OBJECTIVES: To characterize the genetic determinants involved in the reduced susceptibility to ciprofloxacin and cefotaxime in Salmonella enterica serotype Enteritidis clinical isolates obtained from four patients in summer 2003 in Hong Kong. METHODS: Three Salmonella Enteritidis isolates from blood culture and one from stool were collected due to their increased resistance to ciprofloxacin and cefotaxime. PFGE analysis was used to investigate their genetic relatedness. Conjugation experiments were employed to show if the genetic determinants involved were plasmid-mediated. MICs of various antimicrobials were determined by VITEK 2 and Etest. Based on the susceptibility and conjugation experiment results, previously described PCR methods were employed to detect sequences homologous to qnr and bla(CTX-M) suspected to be involved in the reduced susceptibility to ciprofloxacin and cefotaxime, respectively. RESULTS: PFGE analysis showed that the four Salmonella isolates were clonally unrelated. The presence of a qnr-like gene and the CTX-M allele bla(CTX-M-14) on four different transferable plasmids harboured by the four isolates was confirmed. CONCLUSIONS: This is the first report of transferable fluoroquinolone resistance due to a new qnr allele, which appeared to be linked to bla(CTX-M-14), in isolates of Salmonella Enteritidis in Hong Kong.

Transmission of the severe acute respiratory syndrome on aircraft.

BACKGROUND: The severe acute respiratory syndrome (SARS) spread rapidly around the world, largely because persons infected with the SARS-associated coronavirus (SARS-CoV) traveled on aircraft to distant cities. Although many infected persons traveled on commercial aircraft, the risk, if any, of in-flight transmission is unknown. METHODS: We attempted to interview passengers and crew members at least 10 days after they had taken one of three flights that transported a patient or patients with SARS. All index patients met the criteria of the World Health Organization for a probable case of SARS, and index or secondary cases were confirmed to be positive for SARS-CoV on reverse-transcriptase polymerase chain reaction or serologic testing. RESULTS: After one flight carrying a symptomatic person and 119 other persons, laboratory-confirmed SARS developed in 16 persons, 2 others were given diagnoses of probable SARS, and 4 were reported to have SARS but could not be interviewed. Among the 22 persons with illness, the mean time from the flight to the onset of symptoms was four days (range, two to eight), and there were no recognized exposures to patients with SARS before or after the flight. Illness in passengers was related to the physical proximity to the index patient, with illness reported in 8 of the 23 persons who were seated in the three rows in front of the index patient, as compared with 10 of the 88 persons who were seated elsewhere (relative risk, 3.1; 95 percent confidence interval, 1.4 to 6.9). In contrast, another flight carrying four symptomatic persons resulted in transmission to at most one other person, and no illness was documented in passengers on the flight that carried a person who had presymptomatic SARS. CONCLUSIONS: Transmission of SARS may occur on an aircraft when infected persons fly during the symptomatic phase of illness. Measures to reduce the risk of transmission are warranted.

Multivalent antibiotics via metal complexes: potent divalent vancomycins against vancomycin-resistant enterococci.

Dimers of vancomycin (Van), linked by a rigid metal complex, [Pt(en)(H(2)O)(2)](2+), exhibit potent activities (MIC approximately 0.8 mug/mL, approximately 720 times more potent than that of Van itself) against vancomycin-resistant enterococci (VRE). The result suggests that combining metal complexation and receptor/ligand interaction offers a useful method to construct multivalent inhibitors.

Characterization of a laboratory-generated variant of BPS beta-lactamase from Burkholderia pseudomallei that hydrolyses ceftazidime.

Burkholderia pseudomallei produces an Ambler class A beta-lactamase, known as BPS-1. The beta-lactamase gene from a laboratory-derived, ceftazidime-resistant strain of B. pseudomallei (LH-1-2) was cloned and expressed in Escherichia coli. The beta-lactamase, named BPS-1m, had an identical isoelectric focusing point (pI 7.7) to that of BPS-1, but differed in having a stronger hydrolytic activity against ceftazidime. Susceptibility testing showed that BPS-1m when expressed in E. coli conferred resistance to ceftazidime (MIC >or= 32 mg/L). The amino acid sequence of BPS-1m differed from that of BPS-1 by a Pro-to-Ser change at position 167 in the omega loop.